support for ext4/EMMC filesystems in updater binary

Make the mount and format functions take extra parameters describing
the filesystem type and add support for mounting and formatting ext4
filesystems on EMMC.

Change recovery to consistently use stdout for status messages instead
of mixing stdout and stderr.
diff --git a/recovery.c b/recovery.c
index 30bbe38..286f1e5 100644
--- a/recovery.c
+++ b/recovery.c
@@ -673,7 +673,7 @@
 
 static void
 print_property(const char *key, const char *name, void *cookie) {
-    fprintf(stderr, "%s=%s\n", key, name);
+    printf("%s=%s\n", key, name);
 }
 
 int
@@ -683,7 +683,7 @@
     // If these fail, there's not really anywhere to complain...
     freopen(TEMPORARY_LOG_FILE, "a", stdout); setbuf(stdout, NULL);
     freopen(TEMPORARY_LOG_FILE, "a", stderr); setbuf(stderr, NULL);
-    fprintf(stderr, "Starting recovery on %s", ctime(&start));
+    printf("Starting recovery on %s", ctime(&start));
 
     ui_init();
     get_args(&argc, &argv);
@@ -714,14 +714,14 @@
 
     device_recovery_start();
 
-    fprintf(stderr, "Command:");
+    printf("Command:");
     for (arg = 0; arg < argc; arg++) {
-        fprintf(stderr, " \"%s\"", argv[arg]);
+        printf(" \"%s\"", argv[arg]);
     }
-    fprintf(stderr, "\n\n");
+    printf("\n\n");
 
     property_list(print_property, NULL);
-    fprintf(stderr, "\n");
+    printf("\n");
 
     int status = INSTALL_SUCCESS;